Heating element



Sept. 15. l 925-.

V.-G. VAUGHAN HEATING- ELEMENT Filed May 19 INVENTOR for 6. Vaughan, BY v ATTORNEY Fi 2 1s a view in lon itudinal Patented Sept. 15, 1925.

UNITED STATES VICTOR G. VAUGHAN, OF WILKINSBURG, HOUSE ELECTRIC 8: MANUFACTURING VANI-L HEATING Application filed May 19,

To all whom it may concern:

Be it known that I, VICTOR G. VAUGHAN, a citizen of the United States, and a resident of Wilkinsburg, in the county of Alle- 5 gheny and State of Pennsylvania, have invented a new and useful Improvement in Heating Elements, of which the following is a specification.

My invention relates to electrically heated 10 devices ,and particularly to electric heating elements for such devices.

One object'of my invention is to provide an oxidizable coating for a non-oxidiz'able resistor.

Another object of my invention is to provide a heating element that shall comprise a resistor of a non-oxidizable material having an electric-insulating coating thereon of a material that oxidizes at relativelyhigh temperature while still retaining its insulating quality.

other object of my invention is to provide a non-oxidizable resistor having an electric-insulating coating thereon, and means for supporting and holding said resistor in its original normal position in an electrically-heated device.

In practicing my invention, I provide. a supporting member of electric insulating material on which is wound tightly and closely, a helix of an electric resistor, such as nichrome, having a coating of enamel thereon. An external layer of insulating material is tightly wound on a layer of the resistor to hold the turns thereof in their original position after the coating becomes oxidized, dueto the relatively high temperature produced during the operation of the heating element.

In the single sheet of drawings,

Fi re 1 is a view, in side elevation with certain parts cut away, of an electrically heated device having a heating element embodying my invention,

section, of a ating element embodying my invention, and

Fig. 3 is an enlarged view, in longitudinal section, of a portion of a, heating element 3 embodying my invention.

An electrically heated device 11, which is here represented as a curling iron, comprises a tubular barrel 12, a ferrule 13 and a han- PENNSYLVANIA, assrenon ro WESTING- COMPANY, A com-cannon 0E PENNSYL- ELEMENT.

1923. Serial No. 640,057.

dle member 14. A removable tong 15 is operatively mounted thereon, a member or button 16, of a suitableheat-insulating ma terial, being provided at the end adjacent to the handle of the curling iron to permit of the operator actuating the tong against a spring member 17, that is effective to yieldingly maintain the tong in close operative engagement with the barrel 12. I have elected to illustrate the device embodying my invention in connection with a curling iron as it has been developed in connection with such device but its use is not restricted thereto.

A heating element structure 18 for the device comprises a central and longitudinal ly extending metal rod 19 upon which there is mounted a layer 21 of a suitable electricinsulating material, such as mica or micanite, that is adapted to withstand relatively high temperature without deterioration.

A layer 22 of a non-oxidizable resistance material, such as nichrome is Wound upon thelayer 21. The wire 22 is coated with a layer 23 of a suitable electric-insulating enamel, such as has heretofore been extensively used on ordinary electric circuit conductors of relatively small diameter, where the material of the conductor was usually copper.

-The amount of electrical energy that it is desired to translate intoheat is relatively small in a curling iron, usually about 15 watts, and it'has been customary heretofore, to employ a wire of nichrome of approximately .003 or 3 mils in diameter in order to obtain suflicient resistance to limit the current to such a. value on a 110 volt circuit that only 15 watts of energy would be translated into heat. This size of wire permitted the resistor to be so wound as to leave a small space between the adjacent turns, but trouble was experienced in such heating elements by reason of the very small diameter of wire causing it to burn out when subjected to relatively high temperatures.

By providing a coating of enamel on a nichrome conductor that is non-oxidizable,

stance, I employ a mm .005" or 5 mils in I the entire len diameter and still obtain substantially the same electrical resistance as was heretofore obtained with the distributed winding of wire of .003 diameter.

An outer coating24 of a suitable electric-insulating material, such as flexible mica or micanite is tightly wound around the layer of resistance wire 22. An extended helix 25 of a suitable non-oxidizable wire may be wound around the outer surface of the layer 24 in order to further assist in holding the component parts of the heating element in their proper normal operative positions relatively to each other.

One end of the resistor 22 is electrically connected to the metal member 19=at the inner end thereof, as indicated by the numeral 25. The other end of the resistor 22 is brou ht to a terminal'member 26 that is so insu atedly mounted on the metal rod 19 at the other end thereof as to lie within the handle 14. That end of the rod 19 located within the handle 14 and the member 26, constitute the terminals of the hereinbefore described heating element, and a chamber 27 is provided in the handle 14 to permit of the insertion therein of a suitable connector plug for permitting the energization of the heating element in the usual wellknown manner.

The coating 23 of enamel provided over gth of the resistor 22 oxidizes upon the heating element being subjected to the relatively high temperature under which such a device normall operates but the electrical insulating qua ities thereof are retained without any appreciable decrease thereof. The mechanical characteristics of the coating change slightly'in that the coating becomes relatively brittle, but the coatin is maintained in substantially its origina position by the layers 21 and 24 of electr1c insulating material, and further by the fact that the adjacent turns are wound in close operative engagement. The result of this arrangement is that the positions of the turns of wire relatively to each other do not change. By my invention I obtain a heating element comprising a non-oxidizable resistor of greater area of cross-section than I have been able to obtain heretofore, and closely wound relatively to each other, provided with a relatively very thin coating of electric-insulating material which,while becoming oxidized, still retains substantially all of its electric insulating qualities, and which is maintained in its ordinary location around the individual turns of resistor wire under all conditions of operation.

While I have illustrated a particular embodiment of my invention, I have done so only as this is the first device to which my invention has been applied, and it is evident that it may be employed in a large variety of devices and permits of obtaining substantially the same results as I have obtained in the one case. It may be used, for

example, in electric warming pads where the temperature is not high enough to cause the coating to become oxidized. In such a device the wire is sewed on a sheet of flexible material and the coating of electricinsulating material affords additional in sulation and provides an additional safeguard against damage or burnout in case of accidental contact of two parts of the resistor having an a preciable difference of potential between t em.

Various modifications and changes may be made without departing from the spirit and scope of my invention, and I desire, therefore, that only such limitations shall be placed thereon as are imposed by the prior art or are set forth in the appended claims. w

I claim as my invention:

1. A heating element comprising a nonoxidizable resistance conductor having an oxidizable electric insulating coating.

2. A heating element comprising a re sistance conductor of a nickel-chromium alloy having an oxidizable electric-insulating coating.

3. A heating element comprising a nonoxidizable resistor having an electric-insulating coating of a material that oxidizes at a relatively high temperature.

4. A heating element comprising a resistor of a nickel-chromium alloy having thereon an electric-insulating coating of a material that oxidizes at a relatively high temperature.

5. A heating element comprising a. nonoxidizable resistor having thereon a very thin coating of an electric-insulating material that oxidizes at a relatively high temperature.

-6. A heating element comprising a resistance conductor that is non-oxidizable at relatively high temperature and having a coating of electric-insulating material that oxidizes at that temperature.

7. A heating element comprising a supporting means of electric-insulating material a non-oxidizable resistance conductor having an oxidlzable electric-insulating coatmg wound on said supporting means,

and an outer cover member closely surrounda ing said resistance conductor.

8. A heating element comprising a sup porting means of electric-insulating material, a non-oxidizable resistance conductor having an electric-insulating oxidizable coating wound on said support with the adjacent turns thereof in close operative engagement, and means located outside of said win g of resistance conductor for holding thiaturns of said winding in proper oper ativegositions relatively to each other.

9. heating element comprising a supporting means of electric-insulating material, a non-oxidizable resistance conductor having a coating thereon of an electric insulating material that oxidizes at relatively high temperature tightly and closely wound on said supporting means, and an external layer of electric-insulating material for holding said conductor in its initial position after oxidation of said coating.

In testimony whereof, I have hereunto subscribed my name this 15th day of May, 1923.

VICTOR G. VAUGHAN. 

